1. Field of the Invention
The present invention relates to an image forming apparatus for forming hardcopy images based on print data transmitted from external devices (hereinafter referred to as host device), such as, for example, a personal computer, word processor or like data processing device, or an image reading device.
2. Description of the Related Arts
Conventionally, page printers discharge recording sheets (hereinafter referred to as "sheets") bearing formed images based on printer data transmitted from a host device so as to stack the discharged sheets on a receiving table. Page printers are usually Provided a device for accomplishing a sorting operation wherebY the discharged sheets stacked on the receiving table are removed therefrom and sorted (hereinafter referred to as "sorting operation").
That is, conventional page printers are provided with a sorter device for accommodating distributed sheets in a plurality of bins, a reversing device for inverting the top and bottom sides of the sheet and stacking the inverted sheets on a receiving table, and a slide mechanism for moving the receiving table to shift the position of the accommodated sheets.
When, for example, a five-page document and a ten-page document are continuously printed so that a total of 15 sheets are stacked on the receiving table, the operator can readily sort the sheets of the five-page document and the sheets of the ten-page document.
Methods of controlling the aforesaid devices include a method of control accomplished via command data included with the print data transmitted from a host device, a method of control accomplished via discriminating on the page printer side an interrupt in the input of the print data and like methods. In the previously described conventional image forming apparatus, a mechanical device is attached to perform the sorting operation, thereby increasing both the size and the cost of the apparatus.